Containers are used to store a variety of materials, and containers must often meet a wide variety of requirements depending on the intended use. In particular, containers that store perishable materials, such as foods, drinks, pet foods, etc., typically should be able to maintain an airtight seal after the container is filled in order to prevent spoilage of the contents of the container. For example, in the case of metal food cans, the integrity of the can body, the can end walls, and the seams should be maintained during manufacture, filling, cooking, processing, labeling, shipping, displaying, purchasing, home storage, etc. Containers designed to be stacked on top of each other typically should perform all of the functions of non-stackable containers.
Food and beverage containers typically will have at least one closure or can end. One type of food and beverage container is provided with a can end affixed to the container by folding or crimping material that is coupled to the can end with the material of the container body to create a seam such as a double seam. Such can ends may require the use of a tool, such as a can opener, to remove the can end. Other can ends (e.g., “pop-tops”, “pull tops”, easy open ends, converted end, convenience ends, convenience lids, etc.) may be provided with a ring or tab that allows the can end to be removed without the use of a tool. Such a can end may include a structure (e.g., a score, thin connecting metal, etc.) that provides a weakness in the can end that aids in the removal of the can end. In addition, the can end may be a thin sheet of material (e.g., metal foil, etc.) coupled to the container through the use of an adhesive or other mechanism. Another type of food or beverage container is provided with a closure that is affixed to the container primarily by the pressure differential between external atmospheric pressure and a lower internal pressure. Other types of closures (e.g., twist on/off closures, snap on/twist off closures, etc.) are affixed to the container mechanically.
During certain processes, containers are filled with hot, pre-cooked food then sealed for later consumption, commonly referred to as a “hot fill process.” As the contents of the container cool, a vacuum develops inside the container. The resulting vacuum may partially or completely secure the closure to the body of the container. Foods packed with a hot fill process often have certain advantages. For example, end-users often appreciate the convenience of pre-cooked food contents as preparation times are often shorter.
During other processes, containers are filled with uncooked food, sealed, and the food, while in the sealed container, is cooked to the point of being commercially sterilized or “shelf stable.” This process is commonly called a thermal process. During such a process, the required heat may be delivered by a pressurized device, or retort. Thermal processes also have certain advantages. First, the resulting shelf-stable package offers long-term storage of food in a hermetically sealed container. Second, cooking the food inside the container commercially sterilizes the food and the container at the same time. In addition, during some cooking procedures, multiple cans are pushed end to end to move the cans through the heating device. In other processes, metal food cans are rolled to facilitate movement of the cans through the process.
Containers may be stacked for a variety of reasons such as improved display, storage, transport, etc. of the containers. Accordingly, it would be desirable to provide a container having one or more features that provide improved stacking properties.